Species specificity of the immediate hypersensitivity to schistosomal proteolytic enzyme.

An acidic proteolytic enzyme which digests host haemoglobin can be isolated and purified from schistosomes. This small glycoprotein is an allergen which sensitizes the host, as shown by immediate hypersensitivity reactions. These are specific for either Schistosoma haematobium or S. mansoni and can be demonstrated by mast cell degranulation in mice or by intradermal skin tests in monkeys. Although high levels of total IgE may be found in acute and chronic schistosomiasis, there was no evident relationship between the worm burden in monkeys and immediate hypersensitivity reactions to either purified enzyme or crude schistosomal extracts. It is suggested that an in vivo correlation between worm burden and manifestations of the allergic response may be perturbed by high titres of non-specific IgE or other homocytotropic antibodies, thus accounting for false negative skin test reactions. Alternatively, a return to low or subnormal IgE levels may allow the restoration of the allergic response, giving rise to false positive reactions. Purified schistosomal antigens offer certain advantages over crude skin test preparations in terms of uniformity of antigen content, dosage and specificity. In addition, the enzyme may represent a species-specific tool for new immunochemical analyses of schistosomiasis.

Terbutaline: an effective bronchodilator by inhalation.

Ninety-nine patients with severe bronchial asthma were tested with two inhalations of Terbutaline. The peak expiratory flow rate of each was determined by means of the Wright peak flow meter, and compared with a baseline taken previously and recorded. The final results were compared with those obtained in the same patients who alternately had received two inhalations of Salbutamol. The average improvement with Terbutaline was 20% per patient as compared with 16% with Salbutamol, indicating no statistically significant therapeutic difference between the two drugs.

Disodium cromoglycate in immunological mast cell degranulation of mice: an experimental study.

Mast cell degranulation occurs at reproducible percentages when the specific antigen is injected into air bubbles of sensitized mice. A fourfold diminution of the degranulated mast cells was observed when 0.25 cc of a 1% solution of DSCG was injected into the bubble prior to the challenging injection. The difference is statistically significant.